I've tried everything already. Closing and opening the character menu, equipping them one by one while closing the character menu between each item, etc. It simply does not apply the set bonuses. Like Huitrier said, when you equip more than one piece of the set a message appears in the top left corner of the screen saying that the bonus have been applied, but in the character attribute sheet nothing changes. It even says in the "active effects" menu that the bonus is on, but actually it is not, and every time that i load a game then even in the "active effects" menu the bonuses disappears, only remaining the last bonus "applied". For example, if i have 4 parts of the set, only the bonus "applied" (that actually it has not been applied, it just appears in the "active effects" menu) by the 4th part equipped remains. I hope i'm making any sense, hahaha. And i'm using the "Destruction Master" set, btw, and i have 4 parts of the set (out of 7, if i'm not mistaken).